OBJECTIVES: 1. To define the role of heme in the regulation of the synthesis of hemoglobin and other proteins by determining the mechanism by which heme controls the activity of an inhibitory protein kinase that phosphorylates the Met-tRNAfMet binding factor, eIF-2, in immature erythroid cells and non-erythroid cells. 2. To define the role of heme in the regulation of the synthesis and assembly of hemoglobin in normal human erythroid cells and in cells of subjects with iron deficiency, sideroblastic anemias, lead poisoning and alcoholism. 3. To determine the activity and function of the heme-regulated inhibitory protein kinase in the control of protein synthesis in erythroid and non-erythroid cells of normal humans and of subjects with iron-or heme-deficiency. 4. To define the mechanism by which hemin induces erythroid differentiation in Friend erythroleukemia cells.